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Discussion Starter · #1 ·
Hello all.

I'm looking to build my first routered layout. Fairly simple design (as it's my first shot) and I'm after something that'll build and disassemble pretty quickly and easily for storage so a routered layout seems the way forward!!

I would like to include hump back bridges (size and gradient of the scalextric ones), but just wondering if anyone else has achieved this? I don't want big bridges/ elevations, simply hump back bridge size humps on the layout.

After doing a bit of reading it seems 12mm MDF is the best material to build the laout/ main track out of. Ive seen flexible MDF material (in 6 and 8mm depths), but would I have to cut a recess into the original 12mm board to attain a smooth transition? And if I cut it 8mm deep would this lose all rigidity/ strength in the main track section?

I intend to have about a 6ft long straight section (ideally all 1 piece) with x2 humps along the way (each about 1 ft in length with about a 1 inch rise). I don't want the cars to be jumping off the rails, but would like a bit of interest.

Any thoughts/ tips would be good and appreciated. I've seen a lot of people joining a flat track section to a big bridge, but I obviously don't want to do this for such a small humped section as there'd be too many joins!

Hope that makes sense to people. Sorry I'm all a bit new to this.

I look forward to peoples help!!

Cheers,

Si
 

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For a hump it would have to shaped out of a block then routed for slots.
 

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Greg Gaub
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1 inch rise over 1 foot? You should be able to do that with a little kerfing/undercutting. Also, use blocks and weights to slowly form the MDF. If you force it hard, it will snap, but if you give it some time, it will take the shape you want. Of course, thinner MDF makes that easier.
 

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I used a skillsaw to undercut the bottom of my MDF, So there was no filling of the slots. Go check out 'www.oldslotracer.com', he covers this very subject. Just make sure you bring your faverite drink, becuse you will be there awhile.

Another site, but he leans more to larger tracks. www.slotcar.org.uk/trackbuild

One more site, www.slotcar.org/track_builders_building/toa_track_building/main_menu.htm

Between these site and this forum, You should not have a problem.

John W.
 

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An alternative way for making more extreme humps is to laminate thinner MDF. This technique often used to make the curved barriers on tracks, but will also work well for producing humps in the track surface.
Cut a profile of the shape you want, and clamp the thin MDF to it with a good coating of PVA wood glue between each layer. 4 layers of 3mm MDF will give you 12mm thickness. Once the glue is dry it'll be about as rigid as 12mm MDF, set in the shape of the profile.
 

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Discussion Starter · #9 ·
Thank you all for your comments so far.

If I was to make a 6 ft long straight (6 lanes wide) with x2 humps on it, would people recommend using 1 long board made of 12mm mdf? Or use the board and attach seperate sheets on top, such as how Mr Frost has suggested? Maybe routing into the board 4mm to get a smooth transition over the hump/ onto the first layer of mdf and out the other side?

If I just used the 1 board the 'kink' caused by the humps would alter the length of the section therefore making it not match the opposite side.

Again, many thanks for your continued help/ assistance!!

Si
 

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QUOTE (Chris Frost @ 3 Jul 2012, 16:56) <{POST_SNAPBACK}>An alternative way for making more extreme humps is to laminate thinner MDF. This technique often used to make the curved barriers on tracks, but will also work well for producing humps in the track surface.
Cut a profile of the shape you want, and clamp the thin MDF to it with a good coating of PVA wood glue between each layer. 4 layers of 3mm MDF will give you 12mm thickness. Once the glue is dry it'll be about as rigid as 12mm MDF, set in the shape of the profile.
Way to go and you can build the slot as you go so routing is not even needed if it's to be copper taped. That's how I built my 6 ft dia. test loop.
 

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Discussion Starter · #11 ·
Any more info on this method? I get you make a shape/ frame underneath the track, but dont quite get how you make a smooth run-in and out? Also if I route into a 4mm piece, I'm going straight throung the other side???? Any pictures showing 1 layer being built at a time please?

Sorry, I'm all new to this!!

Thanks again all!
 

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You might want to rout in 6mm for grades.
And yes, you do rout through the top layer.

If you keep from routing edge to edge it'll get a lot easier to keep the track integrity while putting it together.
That is, start and end routing a bit from the end. Preferably so that you can just cut those ends off when done.

If using 8mm it's quite possible to rout, or use a circle saw, recesses on the underside. Which will then allow you to form a slope.
And yes, recesses on the underside allow for bending both up and down. And if making a high banked turn.
The closer to each other, the less risk the result look sort of broken up. Ie compare to make a fly over with standard straights and making one with only quarter straights...

It does help to apply a PVA/water mix to the underside.
Soak it in water first (soak is perhaps not the best of terms, but you want it wetter than damp, not so drowned it loosen up the MDF thou) and then PVA/water to make it hold the shape better.


--- Mind you, even if I've used this method several times I would suggest using two 6mm layers instead. ---

Another thing to keep in mind is to start and end the elevation changes some 30 to 50 cm into that piece of track.
Else you'll get a hard job of keeping the edge even across. It's strong and doesn't like this bending business one bit.

And several pieces of support, contoured along (under) the track. Not across (that would lead to the same as just above).
This will prevent the MDF to warp the support under it... Yes, it can very well be strong enough for that.
And that would be plywood(?) for that. As it's rigid the right way.
 

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Discussion Starter · #13 ·
I need 12mm depth, not 6mm for stability. The layout is going to be pretty temporay/ portable. So needs to be 12mm deep really to maintain the overall length/ shape/ structure. I srtill don't get how the layering of thinner boards will work???

Pix anyone please?
 

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If you want any mobility in the track, then 4mm for the slot and 2mm layer glued to it for bottom.
Stability is from the 12×20 spruce(?) lattice work (?) you lay it on.

Yes, 12mm MDF do have a certain amount of stability. But at the cost of mobility.
Remember, even if you can carry the pieces you will push your attention to carrying it instead of where you're carrying it.

How it works with layers?
Think of a spray paint mask... You cut out the track from one sheet and then glue it to the support layer sheet.
 

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I don't think you'll have any problem at all if you take a length of 12mm, route a 6 mm deep slot and then cut a 5mm kerf (full width) in the regions
where you want the 1" hump. It's not really that big of a deal...just screw the middle of the humps down first and progressively screw from either
flat region towards the center until you have the profile of hump you want. There's no problem with adding extra supports in between the center and
flat ends to control the curvature you want.

MDF is very forgiving...just go for it!

best of luck,
John

PS that's how I built my track...not just guessing, it works! Btw, even if you over-stress the material somewhat continue to screw it down and then sand flush
as needed.
 

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Phil Kalbfell
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Even 12 mm will bend without "kerfing" But it takes some time and patience, but I think 9mm may take some effort to bend like a Scalex Hump backed bridge, but 6mm should do it easily.
So laminating two 6mm together is the way to go. I have a 2400 x 1200 rally track made from 9mm that is portable, I can lift it myself. It has 65 x 22 pine around the outside and 4 cross braces of 50 x 22.
 

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I built one with humps late last year.
Look for 'let's have a go at a rally track'



I think this is what you're after? It's very simple. Keep your 12mm and just add to it. I used a belt sander to smooth the transition. Simples!
 
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